The present invention relates generally to hand power tools.
German patent document DE 196 21 610 A1 discloses a hand power tool with a removable tool holder. The hand power tool has a spindle sleeve, in which a base body of the tool holder is insertable and lockable by locking bodies. The locking bodies are non releasably held in the spindle sleeve and are radially covered in a locking position by a securing body. For removing the tool holder, the securing body is displaceable by an actuating sleeve axially to a position which radially releases the locking bodies.
Accordingly, it is an object of the present invention to provide a hand power tool of the above mentioned general type, which is a further improvement of the existing hand power tools.
More particularly, it is an object of the present invention to provide a hand power tool, in which a tool holder is connectable by its base body releasably with a drive part through at least one locking body.
In accordance with the invention, the locking body in its engaging position is radially fixable by a securing body, which is guided by an actuating element for unlocking the tool holder to a position which radially releases the locking bodies.
It is proposed that the base body in its locking position is surrounded by at least a part of the drive part. An anvil can form with the drive part gap seal, which protects the drive unit of the hand power tool from dirt. A low wear can be therefore obtained and damages during insertion of the tool can be avoided. Furthermore, the locking bodies can be mounted on the base body of the tool holder and can be easily replaced or changed with the tool holder when needed.
In accordance with a further embodiment, it is proposed that in the unlocked condition a component holds the locking body in its unlocking position. The tool holder can be easily mounted on the drive part without displacing the locking body. Furthermore, with the component, a recess of the locking body is preferably radially inwardly closed, and a dirtying in the region of the locking body can be avoided, in particular in the dismounted condition. The locking bodies can be loaded in its unlocking position in the locking direction, and thereby an advantageous acoustic and/or optical signal can be provided which signals to a consumer a reliable connection between the tool holder and the drive part. Furthermore, by the position of the locking body, simply a signal can be released through which an energy supply of the hand power tool is controllable. With the not completely mounted tool holder, the energy supply can be interrupted, a damage to the tool can be reliably prevented, and the user can be protected.
Advantageously, several recesses can be arranged over the periphery of the drive part as locking bodies in the base body. Thereby a small turning angle can be obtained during joining the tool holder and the drive part. With the high number of the recesses, the wear of several recesses can be avoided, so that a greater service life can be obtained.
For providing automatic turning of the tool holder to the proper location during fitting of the tool holder on the drive part, the base body and the drive part are advantageously connected through at least one set of teeth in the peripheral direction. In the axial direction they can have reduced contact surfaces, or in other words inclined and/or rounded contact surfaces. The teeth can have a flat contact surfaces in the axial direction and can be guided by hand to a proper position.
Advantageously the base body and the drive part are connected in a peripheral direction via at least one roller mounted on the base body. Instead of the locking body, advantageously the roller can be used as an abutment for the locking bodies in the dismounted condition of the arrestable component, and the locking bodies can be covered in their unlocking position completely by the component in a structural simple manner. Furthermore, a standard component can be used as a roller, and the rotary transmission can be performed in a cost favorable manner.
In accordance with a further embodiment of the present invention, it is proposed that at least one locking body is used for torque transmission. Additional components, as well as structural space, weight and mounting expenses can be saved, or available rotary transmission element can be supported in its function. For example, the locking body formed as a sphere can be guided in a recess formed as a spherical calotte so that a favorable force transmission can be provided. In order to obtain a small surface pressure, the locking body, in addition to being formed as a sphere, can be also formed with different shapes, for example roller-shaped parallelopiped-shaped, etc. A high torque can be transmitted with a simultaneously reduced wear and higher service life.
It is further proposed that the base body has a stepped inner contour to the drive part, and the drive part has a corresponding outer contour. A good guidance and thereby true running are provided by the cylindrical guiding diameter at the front and at the rear receiving region.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.